Thread-controlling mechanisms for sewing machines



A. N. HALE THREAD-CONTROLLING MECHANISMS FOR SEWiNG MACHINES Filed Sept. 19, 1950 2 Sheets-Sheet l WITNESS ATTORNEY Nov. 17, 1953 A. N. HALE 2,659,329

THREAD-CONTROLLING MECHANISMS FOR SEWING MA CHINES Filed Sept. 19 1950 2 Sheets-Sheet 2 g INVENTOR.

- BY zzri/wmz-wuze WITNESS ATTORNEY ?atented Nov. 17, 1953 UNITED STATES PATENT OFFICE THREAD- CONTROLLING MECHANISMS FOR SEWING MACHINES Arthur N. Hale, Stratford, Conn., assignor to The Singer Manufacturing Company, Elizabeth, N. J., a corporation of New Jersey Application September 19, 1950, Serial No. 185,560 7 Claims. (01. 112-199) 2 This invention relates to chain-stitch sewing Journaled in suitable bearings in the bed I machines and more particularly to a thread-conis a bed-shaft I8 which is belt driven, as at trolling mechanism for a thread-carrying looper I9, in the usual manner. An eccentric pin 20, of a two-thread chain-stitch machine. carried by one end of the bed-shaft I8, is con- A primary object of this invention is to pronected by means of a crank link 2! and a rock vide a thread-controlling mechanism of simple arm 22 to a looper-carrier 23 which is journaled inexpensive construction. for oscillation on an axis substantially parallel It is also an object to provide a thread-conto that of the bed-shaft I8. A pair of thread trolling mechanism which may be readily adcarrying loopers 24-44 are supported on the justed to provide a nicety of control of the looperlooper-carrier 23 for oscillatory loop-seizing and thread so as to be suitable for any of a wide -shedding movements in a vertical plane. ran e of stitch-lengths, and to be adapted as As most clearly illustrated in Fig. 3 of the well for the production of tight firm stitches as drawings, a loop spreader periodically engages for the formation of loose elastic stitches. and spreads the limb of each of the looper threads A further object is to provide a mechanism T which constitutes one limb of the usual thread of this character, the parts of which are artriangle entered by a respective one of the neeranged to provide for convenient access thereto, dles. The loop Spreaders comprise a pair of as for threading and adjustment purposes. horizontally disposed spreader-fingers 25-25, one

With the above and other objects in view, as for each of the loopers 2424. The fingers are will hereinafter appear, the invention comprises supported at the forward extremity of a spreaderthe devices, combinations, and arrangements of carrying bar which is journaled for endwise parts hereinafter set forth and illustrated in the sliding movement in lugs 21-2"! formed in the accompanying drawings of a preferred embodibed ID. The rearward extremity of the spreaderment of the invention from which the several carrying bar is formed as a yoke 28 which has features of the invention and the advantages 25 a cylindrical pin 29 freely journaled between the attained thereby will be readily understood by arms thereof. The pin 29 is apertured, normal those skilled in the art. to its longitudinal axis, to slidingly receive a In the drawings: cylindrical rock-arm 30 which extends upwardly Fig. 1 is a front elevational view of a portion from a spreader-driving rock-shaft 3I. The of a sewing machine embodying the present in- 30 rock-shaft 3| is journaled transversely of the vention. bed-shaft I8 in needle-bearings 32-32 provided Fig. 2 represents a vertical section taken subin the front and rear walls I2 and I3 of the bed stantially along the line 22 of Fig. 1. It. Oscillatory movements are imparted to the Fig. 3 is an enlarged top plan view of the forrock-shaft 3| from the bed-shaft I8 by means of ward portion of the machine bed with the clothan eccentric 33 which is secured for rotation plate removed to expose the mechanism within with the bed-shaft by set screws 34-44. Emthe bed. bracing the eccentric 33 is the strap of a pitman Fig. 4 represents a vertical section taken sub- 35, which is formed at its upper end with a splitstantially along the line 4-4 of Fig. 3, showsocket 36 entered by a sleeve-ball 31 apertured ing particularly the looper driving connections. 40 to slidingly accommodate a cylindrical rock-arm The sewing machine of the illustrated embodi- 39 which is secured to the spreader-driving rockment is provided with a frame having a bed shaft 3|. It, which includes a horizontally disposed work- In accordance with the present invention, the

support H and vertical front and rear walls I2 spreader-driving rock-shaft 3| is formed with and I3 respectively. A standard I4 rises from an extension 4c which protrudes through the the bed it and supports an overhanging arm front wall I2 of the bed Iii and is adapted to which terminates in a head I5. Suitable mechactuate the thread-controlling device. To this anism is provided in the overhanging arm for end, the shaft extension 40 is transversely aperimparting vertical reciprocatory and lateral tured to receive a cylindrical shank M of a work-feeding movements toaneedle bar I6 which thread-controlling arm 42. A clamp-screw 43, i journaled in the overhanging arm I5. The which is threaded into a hole 44 formed axially instant invention is adapted for use with either in the rock-shaft 3|, provides means for selecsingle or multi-needle sewing machines and for tively positioning the thread-controlling arm convenience is disclosed in the drawings as apwith respect to the shaft extension 40. The plied to a machine having two needles I'I .I 1. thread-controlling arm 42 is bent at its free exaeoaaae tremity to form a laterally extending portion which is provided with a plurality of spaced thread receiving apertures 46, one for each looper thread. Although four apertures are illustrated in the accompanying drawings, it is apparent that any suitable number may be provided, depending upon the number of looper threads to be accommodated.

Cooperating with the thread-controlling arm 42 is a normally stationary thread-guiding member 41 which is slotted, as at 48, to accommodate a fastening screw 43 threaded into the bed l0. At one extremity, the guiding member 41 is formed with a hook-shaped extension defining spaced limbs 5l, each of which is provided with spaced thread-guiding apertures 52. Preferably, the apertures 52 correspond in number and spacing with the apertures 45 of the threadcontrolling arm 52 which is adapted to cooperate with the limbs 50 and 5| in a manner to be described hereinafter. To provide additional means for guiding the looper threads and for preventing snarling thereof, the stationary thread-guiding member 41, at the side opposite the hook-shaped extension, is formed with an ear 53 which is bent outwardly and provided with spaced thread guiding apertures 54.

The path of the looper-threads from a suitable source of supply located above the machine progresses first downwardly along the machine standard through conventional thread-guiding tubes and then to individual tension devices 55. From the tension devices, the looper-threads are directed to the thread-guiding apertures 52 of limb 5| of the stationary thread-guiding member 41. then through the apertures 46 of the controlling arm 42 and next through apertures 52 of limb 53 of the stationary guide. As the threads continue to the looper they are guided by means of the apertures 54 in the ear 53, the usual thread-guide 51 which is fixed to the bed of the machine, the eyelets 58 at the heels of the lcopers 24 and finally to the eyes of the loopers in the usual manner.

The thread-controlling arm 42, which receives an oscillatory motion from its connection with the loop-spreader driving rock-shaft 32, engages the looper-threads between the stationary thread guiding limbs 50, 5|. The extent of angular movement of the thread-controlling arm 62 is fixed by the eccentric 33 and the rockshaft driving connections therewith. However, in order to provide for an adjustment of the extent of thread-control, the cylindrical shank 4| of the thread-controlling arm may be selectively positioned lengthwise in the shaft-extension 40 to vary the throw of the laterally extending free end 45 of the arm 42. To accommodate such adjustment the thread-controlling arm 42, corresponding lateral adjustments of the normally stationary guide 41 may be made by means of the slot is and fastening screw 49. In addition, the guide M may be selectively adjusted angularly about fastening screw 49 as a pivot in order to change the thread-controlling characteristics of the instant device.

As will be readily apparent to those skilled in the art, the eccentric 33 is timed with respect to the bed-shaft l8 such that the loop-spreader fingers 25-25 occupy an extreme position nearest the standard |4 when the needles are moving downwardly and entering the looper-thread triangles. Moreover, the opposite extreme position of the loop-spreader fingers will occur when the needles are being raised and the loopers are advancing to enter the needle-thread loops. Since the thread-controlling arm 42 and the loopspreader fingers 25-25 are both actuated from the rock-shaft 2|, the extreme positions of each occur simultaneously; in each instance just after one of the stitch-forming instrumentalities has entered the loop formed by the thread of the complemental instrumentality. Thus, without the necessity for a separate timing adjustment, the present construction provides a controlling device which draws out the looper threads at the proper time in the stitching cycle; 1. e. a time when such thread control will cause a minimum of interference with proper p seizure.

Referring to Fig. 1, the thread controlling arm 42 is illustrated by dotted lines in both of its extreme angular positions. As shown in full lines in Fig. 1, the stationary guide is disposed medianly between the extreme positions of the arm 42. Thus, the thread-controlling arm will draw out a quantity of thread between the apertures 46 and 52 twice during each stitch forming cycle, first as it passes above, and second, as it passes below the apertures of the stationary guide-limbs.

It is pointed out that with the instant invention, the adjustment necessary for any particular application depends upon such factors as stitch length, elasticity of seam desired, etc. As an illustration of the versatility of the instant invention, the normally stationary guide 41 may be adjusted angularly to a position in which the thread-guiding apertures 52 of the spaced units 56 and 5| are substantially aligned with the apertures 48 of the thread-controlling arm 42 in one of its extreme positions. With this adjustment, the thread-controlling arm will draw out a quantity of thread only once during each stitch-forming cycle.

Having thus set forth the nature of the invention, what I claim herein is:

1. In a sewing machine having a reciprocatory thread-carrying needle, a thread-carrying looper complemental to said needle in the formation of chain-stitches, and actuating mechanism for operating said needle and said looper including a looper-actuating shaft, a shiftable looperthread loop-spreading member, a looper-thread controlling device having a stationary threadguiding component and a movable thread-engaging element, a common driving member for said loop-spreading member and said threadengaging element, said driving member being arranged transversely of said looper actuating shaft, and an operative connection between said looper actuating shaft and said driving member.

2. In a sewin machine having a bed, a looperactuating shaft supported in said bed, and stitchfcrming instrumentalities including a threadcarrying chain-stitch looper, the combination of a looper-thread loop-spreading member, a loop-spreader actuating rock-shaft journaled in said bed, operative connections between said looper-actuating shaft and said rock-shaft, and a thread-controlling device comprising a threadcontrolling arm secured to said loop-spreader actuating rock-shaft for movement therewith, a thread engaging portion formed on said arm, said portion having an arcuate path of movement about the axis of said rock-shaft, a thread-guiding member fixed to said bed and having spaced thread directing eyelets formed thereon, said eyelets being disposed one at each side of the path of movement of said thread-engaging portion.

3. In a chain-stitch sewing machine of the type employing a thread-carrying looper and having a bed including a work-support, a looperactuating bed-shaft journaled beneath said worksupport, and a wall depending from said worksupp-ort at one side of the bed-shaft, a rock-shaft extending through said vertical wall transversely of said bed-shaft, actuating connections between said bed-shaft and said rock-shaft, an endwise shiftable looper-thread loop-spreader, connections at one side of said wall for actuating said loop-spreader from said rock-shaft, and a looperthread controlling mechanism includin a movable thread-engaging member carried by said rock-shaft at the opposite side of said wall.

4. In a sewing machine having a frame including a work-support and a bed-wall depending from said work-support, stitch-forming mechanism including a thread-carrying chainstitch looper and a spreader, actuating mechanism for operatin said looper including a bedshaft journaled beneath said work-support and to one side of said depending wall, mechanism for operatin said spreader including an actuating shaft extending through said wall transversely of said bed-shaft, and connections at one side of said wall and within the bed for actuating said spreader actuating shaft from said bedshaft, and a thread-controlling device for said looper-thread disposed on the outside of said depending wall, said thread-controlling device comprising spaced stationary thread-guides, and a movable thread-engaging member operating between said thread-guides, said movable member bein carried by said spreader actuating shaft.

5. In a sewing machine having a bed including a work-support and depending front and rear walls, and lower stitch-forming instrumentalities including a thread-carrying looper and a loopspreader disposed beneath said work-support, a looper-actuating bed-shaft disposed beneath said work-support, a rock-shaft journaled in the depending front and rear walls of the bed transverselyof the bed-shaft, an operative connection with the bed-shaft for actuating the transverse shaft, operative connections between the rockshaft and the loop-spreader disposed intermediate the front and rear walls, said rock-shaft extending through one of said depending walls, and a movable looper-thread controlling arm carried by said rock-shaft externally of said wall.

64 A thread-controlling device for a chainstitch sewing machine having lower stitch-forming mechanism including a thread-carrying looper, a spreader and a spreader-actuating rockshaft, comprising a movable arm having one end carried by said spread-actuating rock-shaft, and a stationary thread-guidin member having a hook-shaped portion providing spaced threadguiding limbs between which the movable arm is adapted to operate.

7. A thread-controlling device for a chainstitch sewing machine having lower stitch-forming mechanism including a thread-carrying looper, a spreader and a spreader-actuating rockshaft, comprising a movable arm having one end carried by said spreader-actuating rock-shaft and having its other end bent to form a threadengaging portion having thread directing eyes, and a plate-like stationary thread-guiding memher having a hook-shaped portion providing spaced thread-guiding limbs between which the movable arm is adapted to operate.

ARTHUR N. HALE.

Name Date Zeier Sept. 13, 1949 Number 

